1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device. Note that in this specification, a semiconductor device refers to a semiconductor element itself or a device including a semiconductor element. As an example of such a semiconductor element, for example, a transistor (a thin film transistor and the like) can be given. In addition, a semiconductor device also refers to a display device such as a liquid crystal display device.
2. Description of the Related Art
In recent years, a semiconductor device in which an oxide semiconductor film is used for a channel formation region has attracted great attention (see Patent Documents 1 and 2, for example).